Polyamide

ABSTRACT

A polyamide characterized in that the polyamide is obtained by thermal polycondensation of (a) dicarboxylic acid components comprising 10 to 80% by mole in total carboxylic acid components of 1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of 50/50 to 97/3 and (b) an aliphatic diamine component is disclosed. The alicyclic polyamide having 1,4-cyclohexanedicarboxylic acid in a backbone thereof as a dicarboxylic acid unit, which is suitable as materials for various uses such as automotive parts, electric/electronics parts, industrial materials, engineering materials and daily household goods, and superior in heat resistance, low water absorption, light resistance, moldability and light weight, as well as superior in toughness, chemical resistance and appearance, and molded articles thereof.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/JP01/10693 which has an Internationalfiling date of Dec. 6, 2001, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a new polyamide and molded articlesthereof. In more detail, the present invention relates to a newpolyamide superior in moldability, heat resistance, light resistance andweather resistance, as well as superior in toughness, low waterabsorption, chemical resistance and appearance. The inventive polyamideis also suitable as materials for various uses such as automotive parts,electric/electronics parts, industrial materials, engineering materialsand daily household goods, and molded articles thereof.

PRIOR ART

Polyamides, represented by nylon 6 and nylon 66, have been widely usedas materials for various uses such as clothing, industrial materials,automotive parts, electric/electronics parts and engineering parts, dueto superior moldability, mechanical properties and chemical resistance.

However, with the recent demand for weight reduction of parts, asubstitute for metals used in the parts is molded polyamide. As such,the mechanical properties required for molded articles of polyamide havebeen on the increase. More specifically, conventional nylon 6 and nylon66 are not satisfactory in heat resistance, dimensional stability,mechanical properties and chemical resistance and thus cannot be used atpresent, for example, in an electric/electronics application where aheat resistance for reflow soldering is required along with adevelopment of surface mounting technology (SMT), or an application forunder-hood automotive parts where the requirements have been raised yearafter year.

A polyamide with a high melting point has been proposed to respond tothese demands by solving the problems of the conventional polyamides.More specifically, for example, an aliphatic polyamide with a highmelting point composed of adipic acid and 1,4-butanediamine (which maybe abbreviated as PA46 hereinafter) and a semi-aromatic polyamide with ahigh melting point mainly composed of terephthalic acid and1,6-hexanediamine (which may be abbreviated as 6T type copolyamidehereinafter) have been proposed and some of which are practically used.

However, although PA46 has good moldability and heat resistance, it hasproblems of remarkably large dimensional change and lowering inmechanical properties caused by water absorption. A polyamide composedof terephthalic acid and 1,6-hexanediamine (which may be abbreviated asPA6T type hereinafter) also has a such high melting point as about 370°C., but it is difficult to obtain molded articles with satisfactoryproperties by melt molding due to vigorous thermal degradation of thepolymer itself. Therefore, a 6T type copolyamide having a loweredmelting point in a range of 220 to 340° C. has been developed and usedby copolymerizing PA6T with an aliphatic polyamide such as nylon 6 andnylon 66 or an amorphous aromatic polyamide such as nylon 6I. Said 6Ttype copolyamide really has low water absorption, high heat resistanceand high chemical resistance, but has disadvantages such as inferiormoldabilty, toughness and light resistance. Said copolyamide also has ahigh specific gravity, resulting in a problem in weight reduction.

Furthermore, an alicyclic polyamide with a high melting point composedof 1,4-cyclohexanedicarboxylic acid and 1,6-hexanediamine (which may beabbreviated as PA6C hereinafter) or a semi-alicyclic polyamide composedof said alicyclic polyamide and other nylon has been proposed. Morespecifically, for example, JP-B-47-11073 discloses improvements in heatresistance and mechanical properties by introducing a benzene ring or acyclohexane ring into the molecular chain of the polyamide.JP-A-58-198439 discloses a polyamide composed of1,4-cyclohexanedicarboxylic acid, having a trans/cis ratio of 20/80 to50/50, and undecanonanediamine. RESEARCH DISCLOSURE, P. 405-417 (1991)discloses a polyamide composed of 1,4-cyclohexanedicarboxylic acidhaving a trans ratio of not less than 99% and/or isophthalic acid as acarboxylic acid component, and an aliphatic diamine having carbon atomsof 6 to 9 as a diamine component. A polyamide composed of1,4-cyclohexanedicarboxylic acid having a trans ratio of not less than99% and adipic acid, as a carboxylic acid component, andhexamethylenediamine, as a diamine component, has been also disclosed.Further, JP-A-11-512476 discloses that a semi-alicyclic polyamidecomposed of 1 to 40% of 1,4-cyclohexanedicarboxylic acid, as acarboxylic acid unit, shows an improved heat resistance for soldering.JP-A-9-12868 further discloses that a polyamide composed of adicarboxylic acid unit, in which 1,4-cyclohexanedicarboxylic acid ranges85 to 100% by mole thereof, and an aliphatic diamine as a diamine unitis superior in light resistance, toughness, moldability and heatresistance.

According to the study by the present inventors, an alicyclic polyamidewith a high melting point composed of 1,4-cyclohexanedicarboxylic acidand 1,6-hexanediamine or a semi-alicyclic polyamide, which is acopolymer of said alicyclic polyamide and other nylon, really has, to acertain extent, more improved moldability, heat resistance and lightresistance compared with those of the conventional nylon 6, nylon 66,the aliphatic polyamide having a high melting point or the semi-aromaticpolyamide, but still needs improvement and is insufficient in suchcharacteristics as toughness, dimensional stability in water absorption,chemical resistance and appearance, thus its application is limited atthe moment.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide an alicyclic polyamidehaving 1,4-cyclohexanedicarboxylic acid as a carboxylic acid unit in abackbone thereof, and superior in moldability, heat resistance, lightresistance and weather resistance, as well as superior in toughness, lowwater absorption, chemical resistance and appearance suitable asmaterials for various uses such as automotive parts,electric/electronics parts, industrial materials, engineering materialsand daily household goods, and molded articles thereof.

The present inventors, after an extensive study to solve theabove-described problems, found that the problems described above wereable to be solved by a new alicyclic polyamide obtained bypolycondensation of dicarboxylic acid components containing1,4-cyclohexanedicarboxylic acid having a specified trans/cis molarratio and a diamine component. In particular, the present inventorsfound that a semi-alicyclic polyamide, which was a copolymerizedpolyamide of said alicyclic polyamide with other types of nylon, wasable to effect remarkable improvements, and thus accomplished thepresent invention.

Thus, the present invention relates to a polyamide obtained by thermalpolycondensation of (a) dicarboxylic acid components comprising 10 to80% by mole based on the total carboxylic acid components of1,4-cyclohexanedicarboxylic acid having a specified trans/cis molarratio, and (b) an aliphatic diamine component, and preferably apolyamide wherein a dicarboxylic acid component other than1,4-cyclohexanedicarboxylic acid is an aliphatic dicarboxylic acidhaving 6 to 12 carbon atoms and/or an aromatic dicarboxylic acid and analiphatic diamine component having 4 to 12 carbon atoms.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention relates to a polyamide obtained by thermalpolycondensation of dicarboxylic acid components containing1,4-cyclohexanedicarboxylic acid having a specified trans/cis molarratio and a diamine component.

The polyamide of the present invention is a polymer having amide bonds(—NHCO—) in a main chain thereof. 1,4-Cyclohexanedicarboxylic acid usedin the present invention has a trans/cis molar ratio of 50/50 to 97/3,preferably 50/50 to 90/10, more preferably 55/45 to 90/10 and mostpreferably 70/30 to 90/10. The trans/cis molar ratio of1,4-cyclohexanedicarboxylic acid can be determined by using1,4-cyclohexanedicarboxylic acid as a raw material of the polyamide byhigh performance liquid chromatography (HPLC). More specifically, it canbe determined by separating 1,4-cyclohexanedicarboxylic acid into transand cis components by a gradient elution method using a reversed-phasecolumn to determine each peak area. In more detail, the polyamide ishydrolyzed with an acid such as hydrobromic acid (HBr), followed bytrimethylsilylation (TMS treatment) and gas chromatography measurementto separate into trans and cis components and determine each peak area.A trans/cis molar ratio of 1,4-cyclohexanedicarboxylic acid lower thanthe above-described 50/50 tends to lower toughness and chemicalresistance of the obtained polyamide. Also, a ratio higher than 97/3tends to deteriorate the appearance of molded articles thereof.

The dicarboxylic acid component other than 1,4-cyclohexanedicarboxylicacid unit preferably used in the present invention includes, forexample, an aliphatic dicarboxylic acid such as malonic acid,dimethylmalonic acid, succinic acid, glutaric acid, adipic acid,2-methyladipic acid, trimethyladipic acid, pimelic acid,2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid,sebacic acid, suberic acid, dodecanedicarboxylic acid and eicodionicacid; alicyclic dicarboxylic acid such as 1,3-cyclopentanedicarboxylicacid and 1,3-cyclohexanedicarboxylic acid; and aromatic dicarboxylicacid such as terephthalic acid, isophthalic acid,naphthalenedicarboxylic acid, 2-chloroterephthalic acid,2-methylterephthalic acid, 5-methylisophthalic acid,5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid and diglycolicacid. In the present invention, these dicarboxylic acid components otherthan 1,4-cyclohexanedicarboxylic acid may be used alone or incombination of two or more types thereof. Further, a polyvalentcarboxylic acid having three or more valences, such as trimellitic acid,trimesic acid and pyromellitic acid may be included within a range,which does not deteriorate the object of the present invention. Amongthese dicarboxylic acids, an aliphatic dicarboxylic acid having carbonatoms of 6 to 12 and/or an aromatic dicarboxylic acid is preferable, anduse of adipic acid and/or isophthalic acid is particularly preferable.

The concentration of 1,4-cyclohexanedicarboxylic acid in the presentinvention is 10 to 80% by mole, preferably 10 to 70% by mole and mostpreferably 10 to 60% by mole based on the total dicarboxylic acidcomponents. Among others, a preferable combination of dicarboxylic acidcomponents is 10 to 60% by mole of 1,4-cyclohexanedicarboxylic acid, 20to 90% by mole of adipic acid and 0 to 40% by mole of isophthalic acid,wherein the total of 1,4-cyclohexanedicarboxylic acid, adipic acid andisophthalic acid is 100% by mole. The content of each dicarboxylic acidin the polyamide can be determined for example, by gas chromatography(GC). More specifically, the content can be determined by hydrolyzingthe polyamide with an acid such as hydrobromic acid (HBr), followed bytrimethylsilylation (TMS treatment) and gas chromatography measurementto determine a peak area derived from each component. A content of1,4-cyclohexanedicarboxylic acid in the total dicarboxylic acidcomponents less than 10% by mole tends to lower heat resistance,chemical resistance, light resistance and weather resistance, whereas acontent over 60% by mole tends to deteriorate appearance of moldedarticles thereof.

An aliphatic diamine components preferably used in the present inventionincludes, for example, aliphatic diamines such as ethylenediamine,propylenediamine, tetramethylenediamine, heptamethylenediamine,hexamethylenediamine, pentamethylenediamine, octamethylenediamine,nonamethylenediamine, decamethylenediamine, undecamethylenediamine,dodecamethylenediamine, 2-methylpentamethylenediamine,2,2,4-trimethylhexamethylenediamine,2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine,2,4-dimethyloctamethylenediamine, and 5-methylnonanediamine. Thesealiphatic diamine components may be used alone or in combination of twoor more types thereof. Furthermore, a polyvalent aliphatic diaminecomponent having three or more valences such as bishexamethylenetriaminemay be included within a range, which does not deteriorate the object ofthe present invention. Among these aliphatic diamine components, analiphatic diamine having carbon atoms of 4 to 12 is preferably used anduse of an aliphatic diamine having carbon atoms of 6 to 8 is morepreferable, in particular, use of hexamethylenediamine is mostpreferable.

In the present invention, besides the above-described1,4-cyclohexanedicarboxylic acid and/or dicarboxylic acid componentsother than 1,4-cyclohexanedicarboxylic acid and diamine components, anypolycondensable amino acid and lactam may be used as a copolymerizationcomponent.

The amino acid includes, for example, 6-aminocaproic acid,11-aminoundecanoic acid, 12-aminododecanoic acid andp-aminomethylbenzoic acid. In the present invention, these amino acidsmay be used alone or in combination of two or more types thereof.

The lactam includes, for example, butyrolactam, pivalolactam,caprolactam, capryllactam, enantolactam, undecanolactam anddodecanolactam. In the present invention, these lactams may be usedalone or in combination of two or more types thereof.

In the present invention, a known end capping agent may be added tocontrol molecular weight or improve hot water resistance. As the endcapping agent, a monocarboxylic acid or a monoamine is preferable.Furthermore, an acid anhydride such as phthalic anhydride;monoisocyanate; monohalogenated compound; monoesters; and monoalcoholsare included.

As the monocarboxylic acid which can be used as the end capping agent,any monocarboxylic acid can be used without specific limitation as longas it has reactivity with an amino group, and the monocarboxylic acidincludes, for example, aliphatic monocarboxylic acid such as aceticacid, propionic acid, butyric acid, valeric acid, caproic acid, caprylicacid, lauric acid, tridecylic acid, myristic acid, palmitic acid,stearic acid, pivalic acid and isobutyric acid; alicyclic monocarboxylicacid such as cyclohexanecarboxylic acid; and aromatic monocarboxylicacid such as benzoic acid, toluic acid, α-naphthalene carboxylic acid,β-naphthalene carboxylic acid, methylnaphthalene carboxylic acid andphenylacetic acid. In the present invention, these monocarboxylic acidsmay be used alone or in combination of two or more types thereof.

As the monoamine which is used as the end capping agent, any monoaminecan be used without specific limitation as long as it has reactivitywith a carboxyl group, and the monoamine includes, for example,aliphatic monoamine such as methylamine, ethylamine, propylamine,butylamine, hexylamine, octylamine, decylamine, stearylamine,dimethylamine, diethylamine, dipropylamine and dibutylamine; alicyclicmonoamines such as cyclohexylamine and dicyclohexylamine; and aromaticmonoamines such as aniline, toluidine, diphenylamine and naphthylamine.In the present invention, these monoamines may be used alone or incombination of two or more types thereof.

As a method of thermal polycondensation of the polyamide used in thepresent invention, known methods can be used, and a method of thermalpolycondensation under the condition at a temperature of preferably notlower than 100° C., more preferably not lower than 120° C. and mostpreferably not lower than 170° C. is used. For example, such a method ofthermal melt-polycondensation can be used, where a mixture, a solid saltor an aqueous solution of dicarboxylic acid and diamine such as1,4-cyclohexanedicarboxylic acid and hexamethyleneadipamide isconcentrated by heating at a temperature of 100 to 300° C., while asteam pressure generated is maintained between the normal pressure toabout 5 MPa (in gauge pressure), followed by depressurization at a finalstage to conduct polycondensation under the normal pressure or a reducedpressure. Furthermore, solid phase polymerization method can also beused, where a mixture, a solid salt or a polycondensate of dicarboxylicacid and diamine is subjected to thermal polycondensation at atemperature of not higher than the melting point thereof. These methodsmay be combined if necessary.

As a polymerization system, batch system or continuous system may beused. In addition, there is no limitation in polymerization equipmentand known equipment such as an autoclave type reactor, a tumbler typereactor and an extruder type reactor including a kneader can be used.

Among others, a preferable thermal polycondensation method for obtainingthe polyamide of the present invention is as follows. A mixture, a solidsalt or an aqueous solution of dicarboxylic acid and diamine isproduced, added thereto with a catalyst or an end capping agent ifnecessary, then subjected to thermal polycondensation method at 100 to320° C. to obtain a prepolymer with a number average molecular weight(Mn) of 1,000 to 7,000. The prepolymer is then polymerized in solidphase using a tumbler type reactor or subjected to polycondensation inmolten state under a reduced pressure using an extruder type reactorsuch as a kneader to obtain the polyamide with a number averagemolecular weight (Mn) of 7,000 to 100,000.

When an extruder type reactor such as a kneader is used, an extrusioncondition under a reduced pressure of 0 to 0.07 MPa is preferable. Anextrusion temperature is preferably a temperature of about 1 to 100° C.above the melting point determined by a measurement with differentialscanning calorimetry (DSC) in accordance with JIS K7121. A shear rate ispreferably not lower than about 100 (sec⁻¹) and an average residencetime is preferably about 1 to 15 minutes. Within the above-describedranges, problems such as coloring and failing to achieve a highmolecular weight scarcely occur.

The above-described catalyst is not specifically limited as long as itis known type to be used for polyamide, and includes, for example,phosphoric acid, phosphorous acid, hypophosphorous acid,orthophosphorous acid, pyrophosphorous acid, phenylphosphinic acid,phenylphosphonic acid, 2-methoxyphenylphosphonic acid,2-(2′-pyridil)ethyl-phosphonic acid and metal salts thereof. The metalsalts includes salts of pottassium, sodium, magnesium, vanadium,calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium andantimony, and ammonium salts can also be used. Further, phosphoratessuch as ethyl ester, isopropyl ester, butyl ester, hexyl ester, decylester, isodecyl ester, octadecyl ester, stearyl ester and phenyl estercan also be used.

The molecular weight of the polyamide of the present invention ispreferably 7,000 to 100,000, more preferably 7,500 to 50,000 and mostpreferably 10,000 to 40,000 in number average molecular weight (Mn) fromthe viewpoint of superior moldability and physical properties. Thenumber average molecular weight (Mn) can be determined by gel permeationchromatography (GPC) using hexafluoroisopropanol as a solvent andpoly(methyl methacrylate) (PMMA) as a standard sample of molecularweight. A polyamide having a number average molecular weight (Mn) of notlower than 7,000 tends to suppress lowering in toughness, and apolyamide having Mn not higher than 100,000 tends to suppress loweringin moldability.

Furthermore, the polyamide of the present invention has a molecularweight distribution (Mw/Mn), which is a ratio of weight averagemolecular weight (Mw) and number average molecular weight (Mn)determined by the above-described GPC, in a range of preferably 2 to 6,more preferably 2.5 to 5 and most preferably 3 to 4. The molecularweight distribution (Mw/Mn) not less than 2 provides reduced lowering inchemical resistance and the like, while Mw/Mn not higher than 6 providesreduced lowering in moldability and the like.

Melting point of the polyamide of the present invention is preferably210 to 340° C., more preferably 230 to 330° C., further more preferably250 to 320° C. and most preferably 260 to 300° C. The melting point canbe measured in accordance with JIS K7121. More specifically, it can bedetermined using, for example, DSC-7 equipment made by PERKIN-ELMER INC.as follows. A 8 mg sample is heated up to 400° C. at a heating rate of20° C./min, and a peak temperature in the melting curve thus obtained isdefined as the melting point. When the melting point is not lower than210° C., there is no tendency for lowering the chemical and heatresistance of the polyamide, while having a melting point not higherthan 340° C. provides less possibility of thermal degradation and thelike during molding.

Glass transition temperature of the polyamide of the present inventionis preferably 50 to 110° C., more preferably 50 to 100° C. and mostpreferably 50 to 90° C. The glass transition temperature can be measuredin accordance with JIS K7121. More specifically, it can be determinedusing, for example, DSC-7 equipment made by PERKIN-ELMER INC. asfollows. A sample is first melted on “hotstage” (EP80 made by MettlerInc.), followed by quenching and solidifying the molten sample in liquidnitrogen to prepare a measurement sample. The sample of 10 mg is heatedwithin a range from 30 to 300° C. at a heating rate of 20° C./min tomeasure the glass transition point. When the glass transitiontemperature is not lower than 50° C., there is less tendency forlowering the heat and chemical resistance and less possibility of anincrease in the water absorption capacity, whereas a glass transitiontemperature not higher than 110° C. tends to provide better appearancein molding.

In the present invention, a reinforced polyamide obtained by compoundinginorganic fillers with the polyamide of the present invention also givesremarkable effects, which are the object of the present invention.

The inorganic filler for the reinforced polyamide of the presentinvention is not specifically limited, and preferable examples thereofinclude glass fiber, carbon fiber, wollastonite, talc, mica, kaolin,barium sulfate, calcium carbonate, apatite, sodium phosphate, fluorite,silicon nitride, potassium titanate, molybdenum disulfide and apatite.Among others, glass fiber, carbon fiber, wollastonite, talc, mica,kaolin, boron nitride, potassium titanate and apatite are preferablyused from the viewpoint of physical properties, safety and cost.

Among the above-described glass fiber and carbon fiber, the fibershaving a number average fiber diameter of 3 to 30 μm, a weight averagefiber length of 100 to 750 μm and an aspect ratio (L/D), that is a ratioof weight average fiber length to average fiber diameter, of 10 to 100are most preferably used from the viewpoint of giving the polyamidesuperior characteristics. Further, when wollastonite is used, it is mostpreferred to have a number average fiber diameter of 3 to 30 μm, aweight average fiber length of 10 to 500 μm and the above-describedaspect ratio (L/D) of 3 to 100. Moreover, with regard to talc, mica,kaolin, silicon nitride and potassium titanate, those having a numberaverage fiber diameter of 0.1 to 3 μm are most preferably used.

In particular, the above-described inorganic fillers of surface treatedtypes are preferably used.

As a surface treatment agent, a coupling agent or a film-forming agentis used.

The coupling agent includes silane-based coupling agent andtitanium-based coupling agent.

The silane-based coupling agent includes triethoxysilane,vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane,β-(1,1-epoxycyclohexyl)ethyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane,γ-amino-propyltriethoxysilane, N-phenyl-γ-aminopropyl-trimethoxy silane,γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane,γ-aminopropyltrimethoxysilane,γ-aminopropyl-tris(2-methoxy-ethoxy)silane,N-methyl-γ-aminopropyltrimethoxysilane,N-vinylbenzyl-γ-aminopropyltriethoxysilane,triaminopropyltrimethoxysilane, 3-ureidopropyl-trimethoxysilane,3-(4,5-dihydroimidazole)propyl-triethoxysilane, hexamethyldisilazane,N,O-bis(trimethylsilyl)amide and N,N-bis(trimethylsilyl)urea. Amongothers, aminosilane and epoxysilane such asγ-aminopropyl-trimethoxysilane,N-β-(aminoethyl)-γ-aminopropyl-trimethoxysilane,γ-glycidoxypropyl-trimethoxysilane,β-(1,1-epoxycyclohexyl)ethyltrimethoxysilane and the like are preferablyused due to economical advantage and easy handling.

The titanium-based coupling agent includes isopropyltriisostearoyltitanate, isopropyltridecylbenzeneslufonyl titanate,isopropyltris(dioctylpyrophosphate) titanate,tetraisopropylbis(dioctylphosphite) titanate,tetraoctylbis(ditridecylphosphite) titanate,tetra(1,1-diallyloxymethyl-1-butyl)bis(ditridecyl-phosphite)titanate,bis(dioctylpyrophophate)oxyacetate-titanate,bis(dioctylpyrophophate)ethylene titanate, isopropyltrioctanoyltitanate, isopropyldimethacrylisosteraoyl titanate,isopropylisostearoyldiacryl titanate, isopropyltri(dioctylphosphate)titanate, isopropyltricumylphenyl titanate,isopropyltri(N-amidoethylaminoethyl) titanate, dicumylphenyloxyacetatetitanate and diisostearoyl-ethylene titanate and the like.

The film forming agent includes polymers such as urethane type polymers,acrylic acid-based polymers, copolymers of maleic anhydride and anunsaturated monomer such as ethylene, styrene, α-methylstyrene,butadiene, isoprene, chloroprene, 2,3-dichlorobutadiene, 1,3-pentadieneand cyclooctadiene, epoxy polymers, polyester polymers, vinylacetate-based polymers and polyether polymers. Among others, inparticular, urethane polymers, acrylic acid-based polymers andcopolymers of maleic anhydride and butadiene, ethylene and styrene andmixtures thereof are preferably used from the viewpoints of economicaladvantage and superior performances.

The inorganic fillers may be surface treated using the above-describedcoupling agents and film forming agents by well known methods includingsizing treatment in which a solution or a suspension of theabove-described coupling agent and film forming agent in an organicsolvent is surface-coated as a sizing agent, dry mixing method forcoating the same using a Henschel mixer, super mixer, Laydy mixer ortwin-cylinder mixer and spray method for spray coating the same as wellas integral blend method and dry concentrate method. A combined methodthereof may also be included, for example, coating of a coupling agentand a part of a film forming agent by sizing treatment followed byspraying the remainder of the film forming agent. Among them, inparticular, sizing treatment, dry mixing, spraying method and a combinedmethod thereof are preferably used from the viewpoint of economicaladvantage.

The method for producing the above-described reinforced polyamide is notspecifically limited as long as it is a mixing method for the polyamideof the present invention and inorganic fillers. For example, the meltmixing temperature is preferably about 250 to 350° C. as a resintemperature and the melt mixing time is preferably about 1 to 30minutes. Further, the feeding method for the components of thereinforced polyamide into a melt mixing equipment may be a simultaneousfeed system of all components into the same feeding port or a method tofeed each component from different feeding ports, respectively. Morespecifically, the mixing method includes, for example, a method formixing the polyamide and inorganic fillers using a Henschel mixer andthe like, followed by feeding them into a melt mixing equipment tocomplete kneading, or a method for compounding inorganic fillers from aside feeder into the polyamide in molten state in a single screw or atwin screw extruder.

As the melt mixing equipment, known equipment can be used. For example,single screw or twin screw extruder, Banbury mixer and mixing roll arepreferably used.

The number average fiber diameter and weight average fiber length of theinorganic fillers can be determined by dissolving the molded article ina solvent for the polyamide such as formic acid, optionally selecting100 or more fibers of inorganic fillers from the insoluble components,and examining them using an optical microscope or a scanning electronmicroscope.

The amount of inorganic fillers to be compounded is 5 to 500 parts byweight, preferably 10 to 250 parts by weight and more preferably 10 to150 parts by weight based on 100 parts by weight of the polyamide. Acompounding amount not less than 5 parts by weight provides sufficientlyimproved mechanical properties, while a compounding amount not higherthan 500 parts by weight provides less lowering in moldability.

In the polyamide or the reinforced polyamide of the present invention,other resins may be mixed, if necessary, within a range that does notdeteriorate the object of the present invention. Said other resin to becompounded is preferably a thermoplastic resin and a rubber component.

The above-described thermoplastic resin includes, for example,polystyrenic resins such as atactic polystyrene, isotactic polystyrene,syndiotactic polystyrene, AS resin and ABS resin; polyester resins suchas poly(ethylene terephthalate) and poly(butylene terephthalate);polyamide such as nylon 6, 66, 612 and 66/6I; polyether resins such aspolycarbonate, polyphenylene ether, polysulfone and polyethersulfone;condensation resins such as poly(phenylene sulfide) andpolyoxymethylene; acrylic resins such as poly(acrylic acid),polyacrylate and poly(methyl methacrylate); polyolefinic resins such aspolyethylene, polypropylene, polybutene and ethylene-propylenecopolymer; halogen containing resins such as poly(vinyl chloride) andpoly(vinylidene chloride); phenol resin; and epoxy resin.

The rubber component includes, for example, natural rubber,polybutadiene, polyisoprene, polyisobutylene, Neoprene, polysulfiderubber, thiokol rubber, acrylic rubber, urethane rubber, siliconerubber, epichlorohydrin rubber, styrene-butadiene block copolymer (SBR),hydrogenated styrene-butadiene block copolymer (SEB),styrene-butadiene-styrene block copolymer (SBS), hydrogenatedstyrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene blockcopolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP),styrene-isoprene-styrene block copolymer (SIS), hydrogenatedstyrene-isoprene-styrene block copolymer (SEPS), styrene-butadienerandom copolymer, hydrogenated styrene-butadiene random copolymer,styrene-ethylene-propylene random copolymer, styrene-ethylene-butylenerandom copolymer, ethylene-propylene copolymer (EPR),ethylene-(1-butene)copolymer, ethylene-(1-hexene) copolymer,ethylene-(1-octene)copolymer and ethylene-propylenediene copolymer(EPDM); and core-shell type of rubber such asbutadiene-acrylonitrile-styrene core-shell rubber (ABS), methylmethacrylate-butadiene-styrene core-shell rubber (MBS), methylmethacrylate-butyl acrylate-styrene core-shell rubber (MAS), octylacrylate-butadiene-styrene core-shell rubber (MABS), alkylacrylate-butadiene-acrylonitrile-styrene core-shell rubber (AABS),butadiene-styrene core-shell rubber (SBR) and siloxane containing rubbersuch as methyl methacrylate-butyl acrylatesiloxane.

Modified forms of the above-described other resins and rubber componentsare also preferably used. The modified form means the above-describedother resin and rubber component is modified with a modifier having apolar group, and includes, for example, polypropylene modified withmaleic anhydride, polyphenylene ether modified with maleic anhydride,polypropylene modified with maleic anhydride, SEBS modified with maleicanhydride, SEPS modified with maleic anhydride, ethylene-propylenecopolymer modified with maleic anhydride, ethylene-(1-butene) copolymermodified with maleic anhydride, ethylene-(1-hexene) copolymer modifiedwith maleic anhydride, ethylene-(1-octene) copolymer modified withmaleic anhydride, EPDM modified with maleic anhydride, SEBS modifiedwith epoxy group, ethylene-propylene copolymer modified with epoxygroup, ethylene-(1-butene) copolymer modified with epoxy group,ethylene-(1-hexene) copolymer modified with epoxy group andethylene-(1-octene) copolymer modified with epoxy group. These otherresin and rubber component and modified forms thereof may be compoundedalone or in combination of two or more types thereof.

Various additives used for usual polyamide resins can be added, ifnecessary, within a range not to impair the object of the presentinvention. The additives include, for example, flame retardant such asantimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate,zinc stannate, zinc hydroxystannate, ammonium polyphosphate, cyanuricmelamine, succinoguanamine, melamine polyphosphate, melamine sulfate,melamine phthalate, aromatic polyphosphates and composite glass powder;pigment or colorant such as titanium white and carbon black;phosphite-based stabilizer such as phosphite esters; heat stabilizersuch as hindered phenol and hindered amine; heat resistance improvingagent such as cuprous iodide and potassium iodide; moldability improvingagent such as calcium stearate, calcium montanate, stearyl stearate anderucic acid amide; plasticizers; weather resistance improving agent; andantistatic agent.

Molded articles of the polyamide of the present invention or compositionthereof can be obtained using commonly known plastic molding methods,such as compression molding, injection molding, gas assisted injectionmolding, welding, extrusion, blow molding, film forming, hollow molding,multi-layer molding and melt spinning.

The molded article of the present invention can also be used preferablyas a molded body with a coated film on the surface thereof due tosuperior surface appearance. Any coating method can be suitably usedwithout specific limitation as long as it is a known method. The methodincludes, for example, a spray method and electrostatic coating method.Further, any coating material can be suitably used without specificlimitation as long as it is a known material, including coatingmaterials such as melamine-curable polyester-polyol resin type andacryl-urethane type.

The molded articles of the polyamide of the present invention orcompound thereof are superior in heat resistance, light resistance andweather resistance, as well as superior in toughness, low waterabsorption, chemical resistance and appearance. Therefore, it isexpected to be suitably used in industrial machinery parts such as agear and cam; electric/electronics parts such as a connector, switch,relay, MID, printed circuit board and housing for electronics parts; andextrusion applications such as a film, sheet, filament, tube, rod andblow molded articles. It is also expected to be suitably used asautomotive parts such as interior parts/outer/panels/exterior parts,under-hood parts and electric equipment parts.

Hereinbelow, the present invention will be described in more detailusing Examples, but it should not be construed to be limited by thefollowing Examples as long as the gist of the present invention ismaintained. Physical properties shown in the following Examples andComparative Examples were evaluated as follows.

(1) Trans/Cis Molar Ratio of 1,4-cyclohexanedicarboxylic Acid

HPLC (high performance liquid chromatography) equipment (LC-10A made byShimadzu Corp.) was used. 1,4-Cyclohexanedicarboxylic acid monomer wasseparated into a trans component (elution time of about 11 minutes) anda cis component (elution time of about 14.5 minutes) by a gradientelution method using reversed-phase column, and thus said ratio wasdetermined from a ratio of area of each peak. Detailed conditions ofHPLC analysis are as follows:

Equipment: LC-10A vp made by Shimadzu Corp.; Reversed-phase DevelosilPRAQUOUS made by Nomura (C30) column: Chemical Co. Ltd.; Temperature:40° C.; Flow rate: 1.0 ml/min; Detection: UV 214 nm; Mobile phase A:Water [0.1% by weight of trifluoroacetic acid (TFA)]; Mobile phase B:Water/acetonitrile = 10/90 parts by weight, [0.1% by weight oftrifluoroacetic acid (TFA)]; Mixing ratio of B = 0 → 100% (over 15minutes); mobile phases: Sample concentration: 10 mg/ml, solvent:water/acetonitrile = 50/50); Injection volume 20 ml. of sample solution:(2) Characteristics of the Polyamide(2-1) Number Average Molecular Weight (Mn) and Molecular WeightDistribution (Mw/Mn)

These characteristics were determined by gel permeation chromatography(GPC) using the polyamide or molded articles thereof under the followingconditions.

Equipment: HLC-8020 made by TOSOH CORP.; Detector: Differentialrefractive index meter (RI); Solvent: Hexafluoroisopropanol dissolving0.1% by mole of sodium trifluoroacetate; Column: Two TSKgel-GMHHR-H andone G1000HHR made by TOSOH CORP.; Solvent flow rate: 0.6 ml/min; Sample1 to 3 (mg sample)/1 (ml solvent). concentration:

Insoluble components were removed by filtration to prepare measurementsamples. Number average molecular weight (Mn) and weight averagemolecular weight (Mw) were determined based on elution curve obtained byusing polymethyl methacrylate as a standard sample. The value of (Mw/Mn)was calculate by dividing Mw by Mn.

(2-2) Specific Gravity (Kg/m³)

Specific gravity of an injection molded test piece was measured usingthe specific gravity measuring equipment (SD-120L made by MIRAQE).

(2-3) Melting Point (° C.), Heat of Melting (J/g) and CrystallizationTemperature (° C.)

These properties were measured in accordance with JIS K7121 and K7122using Model DSC-7 made by PERKIN-ELMER INC. Measurement was conductedaccording to the following procedure: A sample of about 10 mg was heatedat a heating rate of 20° C./min under nitrogen atmosphere to obtain anendothermic peak (melting peak), which was defined as Tm¹ (° C.). Thesample was kept in a melt state at a temperature of Tm¹+40° C. for 2minutes, then cooled down to 30° C. at a cooling rate of 20° C./min toobtain an exothermic peak (crystallization peak), which was defined ascrystallization temperature. Subsequently, the sample was kept at 30° C.for 2 minutes, followed by heating at a heating rate of 20° C./min toobtain a peak (melting peak), which was defined as melting point Tm² (°C.). Heat of melting was determined from a peak area thereof.

(2-4) Glass Transition Temperature (° C.)

Glass transition temperature was measured in accordance with JIS K7121using Model DSC-7 made by PERKIN-ELMER INC. A sample was first melted ona hot stage (EP80 made by Mettler Inc.), then the sample in molten statewas quenched and solidified in liquid nitrogen to prepare a measurementsample. Glass transition temperature was measured by heating 10 mg ofthe sample in a range from 30 to 300° C. at a heating rate of 20°C./min.

(2-5) Water Absorption Ratio (% by Weight)

Water absorption ratio was determined by measuring weights before andafter immersing a sample in water at 23° C. for 24 hours. Morespecifically, water absorption ratio was obtained by dividing a weightincrease after the immersion by a weight of the sample in an absolutedry condition.

(3) Preparation of Molded Article and Physical Properties Thereof

Molded article was prepared using injection molding machine, PS40E madeby Nissei Plastic Ind. Co., Ltd. Molded article was obtained under thefollowing injection molding conditions: Mold temperature: 120° C.;injection time: 17 seconds; cooling time: 20 seconds. Cylindertemperature was set at a temperature of about 30° C. above the meltingpoint of the polyamide determined in accordance with the above-describedprocedure (1-1).

(4) Mechanical Properties of the Polyamide

(4-1) Tensile Strength (MPa) and Tensile Elongation (%)

These properties were measured in accordance with ASTM D638.

(4-2) Flexural Modulus (GPa)

This property was measured in accordance with ASTM D790.

(4-3) Notched Izod Impact Strength (J/m)

This property was measured in accordance with ASTM D256.

(4-4) Heat Deflection Temperature (° C.)

This property was measured in accordance with ASTM D648 under a load of1.86 MPa.

(4-5) Chemical Resistance

Chemical resistance was evaluated by measuring a depth of crack after atreatment with calcium chloride. More specifically, a dumbbell-shapedinjection molded test piece (3 mm thick) was immersed in water at 80° C.for 8 hours, then weights were hung down at both ends thereof so thatstress of 19.6 MPa was loaded at the support point (which was apart by10 cm from the weight-hanging ends). Further, a gauze of 74 mm×74 mm wasattached on the support area (after folded two times to a rectangularshape of 37 mm×18 mm), on which 1 ml of 30% by weight of calciumchloride aqueous solution was dropped. The test piece was placed in anoven (100° C.) for 2 hours, then a depth of the resulting crack on thetest piece was measured.

(4-6) Light Resistance

Light resistance was evaluated by calculating retention (%) from tensilestrengths before and after irradiation of UV light of a wavelength of254 nm for 1 hour at a distance of 1 mm from the surface ofdumbbell-shaped injection molded test piece for tensile strengthmeasurement.

(4-7) Surface Appearance

Surface appearance was evaluated by measuring Gs 60° C. in accordancewith JIS-K7150 using a handy gloss meter IG320 made by Horiba Ltd.

EXAMPLE 1

In 3,000 ml of distilled water, 500.4 g (2.906 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 637.4 g (4.360 mole) of adipic acid and 844.3 g (7.266 mole) ofhexamethylenediamine were dissolved to prepare an aqueous solution witha neutralization equivalent point of pH=7.80 at 60° C. The aqueoussolution was charged in a 6L autoclave, which was purged with nitrogen.The solution was then concentrated, while stirred at 110 to 150° C., bygradually removing steam until the concentration of the solution reached70% by weight. Then the temperature was raised to 218° C. and pressurewas raised to 22 Kg/cm² in the autoclave. Reaction was continued for 1additional hour until the temperature reached 253° C., while thepressure was maintained at 22 Kg/cm² by gradually removing steam toobtain a prepolymer with a number average molecular weight (Mn) of5,000. This prepolymer was crushed to pieces having a size not largerthan 3 mm and dried at 100° C. for 24 hours, under nitrogen gas streamat a flow rate of 20 L/min. Subsequently, the prepolymer was subjectedto solid phase polymerization at 210° C. for 10 hours under nitrogen gasstream at a flow rate of 200 ml/min to obtain a polyamide. Resultsobtained are shown in Table 1.

EXAMPLE 2

A polyamide was polymerized and molded according to the same method asin Example 1 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 65/35 was used. Results obtained are shown inTable 1.

EXAMPLE 3

A polyamide was polymerized and molded according to the same method asin Example 1 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 55/45 was used. Results obtained are shown inTable 1.

EXAMPLE 4

A polyamide was polymerized and molded according to the same method asin Example 1 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 95/5 was used. Results obtained are shown inTable 1.

COMPARATIVE EXAMPLE 1

A polyamide was polymerized and molded according to the same method asin Example 1 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 20/80 was used. Results obtained are shown inTable 1.

COMPARATIVE EXAMPLE 2

A polyamide was polymerized and molded according to the same method asin Example 1 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 99.7/0.3 was used. Results obtained are shownin Table 1.

EXAMPLE 5

A polyamide was polymerized and molded according to the same method asin Example 1 except that 750.8 g (4.360 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 424.9 g (2.906 mole) of adipic acid and 844.3 g (7.266 mole) ofhexamethylenediamine were used. Results obtained are shown in Table 2.

EXAMPLE 6

A polyamide was polymerized and molded according to the same method asin Example 1 except that 187.7 g (1.090 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 902.9 g (6.176 mole) of adipic acid and 844.3 g (7.266 mole) ofhexamethylenediamine were used. Results obtained are shown in Table 2.

COMPARATIVE EXAMPLE 3

A polyamide was polymerized according to the same method as in Example 1except that 1363.8 g (7.266 mole) of 1,4-cyclohexanedicarboxylic acidhaving a trans/cis molar ratio of 80/20 and 844.3 g (7.266 mole) ofhexamethylenediamine were used. Melting point was measured in accordancewith the method described in (2-3). Tm¹ was 412° C. but Tm² was notdetected. The sample could not be molded because Tm¹ was over 400° C.

COMPARATIVE EXAMPLE 4

A polyamide was polymerized and molded according to the same method asin Example 1 except that 62.6 g (0.363 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 1,009.1 g (6.903 mole) of adipic acid and 844.3 g (7.266 mole) ofhexamethylenediamine were used. Results obtained are shown in Table 2.

EXAMPLE 7

In 3,000 ml of distilled water, 1,251.2 g (7.266 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of 80/20and 1,048.2 g (7.266 mole) of octamethylenediamine were dissolved toprepare an aqueous solution with a neutralization equivalent point ofpH=7.80 at 60° C. The solution was charged in a 6L autoclave, which waspurged with nitrogen. The solution was then concentrated, while beingstirred at 110 to 150° C., by gradually removing steam until theconcentration of the solution reached 70% by weight. Then thetemperature was raised to 218° C. and pressure was raised to 22 Kg/cm²in the autoclave. The reaction was continued for 1 additional hour untilthe temperature reached 253° C., while the pressure was maintained at 22Kg/cm² by gradually removing steam to obtain a prepolymer with a numberaverage molecular weight (Mn) of 5,000. This prepolymer was crushed topieces having a size not larger than 3 mm and dried at 100° C. for 24hours, under nitrogen gas stream at a flow rate of 20 L/min. The driedprepolymer was extruded using a kneader type reaction extruder (BT-30made by Plastic Engineering Institute Co. Ltd.) under the conditions of300° C., reduced pressure of 0.03 MPa and residence time of 10 minutesto obtain a polyamide. Results obtained are shown in Table 3.

EXAMPLE 8

A polyamide was polymerized and molded according to the same method asin Example 7 except that 1,150.1 g (7.266 mol) of nonamethylenediaminewas used instead of octamethylenediamine in Example 7. Results obtainedare shown in Table 3.

EXAMPLE 9

A polyamide was polymerized and molded according to the same method asin Example 7 except that 1,455.9 g (7.266 mol) of dodecamethylenediaminewas used instead of octamethylenediamine in Example 7. Results obtainedare shown in Table 3.

EXAMPLE 10

In 3,000 ml of distilled water, 250.2 g (1.453 mole) of1,4-cyclohexanedicarboxylic acid which has a trans/cis molar ratio of80/20, 849.8 g (5.813 mole) of adipic acid and 1,354.4 g (7.266 mole) ofundecamethylenediamine were dissolved at 60° C. to prepare an aqueoussolution. A polyamide was polymerized and molded using this aqueoussolution according to the same method as in Example 7. Results obtainedare shown in Table 3.

COMPARATIVE EXAMPLE 5

A polyamide was polymerized and molded according to the same method asin Example 7 except that 1,363.8 g (7.266 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of 20/80was used. Results obtained are shown in Table 4.

COMPARATIVE EXAMPLE 6

In 2,688 ml of distilled water, 1,251.2 g (7.266 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of 50/50and 1,354.4 g (7.266 mole) of undecamethylenediamine were dissolved at60° C. to prepare an aqueous solution. A polyamide was polymerized andmolded according to the same method as in Example 7 except that thisaqueous solution was used. Results obtained are shown in Table 4.

COMPARATIVE EXAMPLE 7

In 2,688 ml of distilled water, 1,063.5 g (6.176 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of20/80, 159.3 g (1.090 mole) of adipic acid and 1,354.4 g (7.266 mole) ofundecamethylenediamine were dissolved at 60° C. to prepare an aqueoussolution. A polyamide was polymerized and molded according to the samemethod as in Example 7 except that this aqueous solution was used.Results obtained are shown in Table 4.

EXAMPLE 11

In 2,731 ml of distilled water, 132.4 g (0.769 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 1,206.3 g (8.254 mole) of adipic acid, 132.4 g (0.797 mole) ofisophthalic acid and 1,141.1 g (9.820 mole) of hexamethylenediamine weredissolved to prepare an aqueous solution with a neutralizationequivalent point of pH=7.56 at 60° C. The aqueous solution was chargedin a 6L autoclave, which was purged with nitrogen. The solution was thenconcentrated, while being stirred at 110 to 150° C., by graduallyremoving steam until the concentration of the solution reached 70% byweight. Then the temperature was raised to 218° C. and pressure wasraised to 18 Kg/cm² in the autoclave. The reaction was continued for 1additional hour until the temperature reached 253° C., while thepressure was maintained at 18 Kg/cm² by gradually removing steam. Thenthe pressure was lowered to 1 Kg/cm² over 1 hour and the polymerizationwas continued for 15 additional minutes while nitrogen gas was made toflow in the autoclave to obtain a polyamide. This polyamide was crushedto pieces having a size not larger than 2 mm, and dried at 100° C. for12 hours under the nitrogen atmosphere. Results obtained are shown inTable 4.

EXAMPLE 12

A polyamide was polymerized and molded according to the same method asin Example 11 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 60/40 was used. Results obtained are shown inTable 5.

EXAMPLE 13

In 2,688 ml of distilled water, 220.7 g (1.282 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 1.029.9 g (7.047 mole) of adipic acid, 220.7 g (1.328 mole) ofisophthalic acid and 1,122.1 g (9.657 mole) of hexamethylenediamine weredissolved to prepare an aqueous solution with a neutralizationequivalent point of pH=7.56 at 60° C. A polyamide was polymerized andmolded according to the same method as in Example 11 except that thisaqueous solution was used. Results obtained are shown in Table 5.

EXAMPLE 14

In 2,688 ml of distilled water, 498.9 g (2.897 mole) of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of80/20, 564.6 g (3.863 mole) of adipic acid, 481.5 g (2.897 mole) ofisophthalic acid and 1,122.1 g (9.657 mole) of hexamethylenediamine weredissolved to prepare an aqueous solution with a neutralizationequivalent point of pH=7.56 at 60° C. A polyamide was polymerized andmolded according to the same method as in Example 11 except that thisaqueous solution was used. Results obtained are shown in Table 5.

COMPARATIVE EXAMPLE 8

A polyamide was polymerized and molded according to the same method asin Example 11 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 99.7/0.3 was used. Results obtained are shownin Table 6.

COMPARATIVE EXAMPLE 9

A polyamide was polymerized and molded according to the same method asin Example 11 except that 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 45/55 was used. Results obtained are shown inTable 6.

COMPARATIVE EXAMPLE 10

In 2,800 ml of distilled water, 132.4 g (0.797 mole) of terephthalicacid, 1,206.3 g (8.254 mole) of adipic acid, 132.4 g (0.797 mole) ofisophthalic acid and 1,144.4 g (9.848 mole) of hexamethylenediamine weredissolved to prepare an aqueous solution with a neutralizationequivalent point of pH=7.17 at 60° C. A polyamide was polymerized andmolded according to the same method as in Example 11 except that thisaqueous solution was used. Results obtained are shown in Table 6.

COMPARATIVE EXAMPLE 11

In 2,616 ml of distilled water, 1,206.3 g (8.254 mole) of adipic acid,264.8 g (1.594 mole) of isophthalic acid and 1,144.4 g (9.848 mole) ofhexamethylenediamine were dissolved to prepare an aqueous solution witha neutralization equivalent point of pH=7.15 at 60° C. A polyamide waspolymerized and molded according to the same method as in Example 11except that this aqueous solution was used. Results obtained are shownin Table 6.

EXAMPLE 15

Using 100 parts by weight of the polyamide obtained in Example 1 and 40parts by weight of glass fiber with a diameter of 10 μm and an averagelength of 3 mm (ECS03T275 GH made by Nippon Electric Glass Co., Ltd.),dry blend was carried out. This blend was melt mixed and pelletizedusing a co-rotating twin screw extruder TEM35 (L1/D1=47) made by ToshibaMachine Co., Ltd., under conditions of cylinder temperature=320° C. andrevolution speed=400 rpm to produce a polyamide composition. Resultsobtained are shown in Table 7.

EXAMPLE 16

A composition was prepared by compounding glass fiber into a polyamideaccording to the same method as in Example 14 except that the polyamideobtained in Example 11 was used, then injection molding of thecomposition was carried out. Results obtained are shown in Table 7.

EXAMPLE 17

Using 100 parts by weight of the polyamide obtained in Example 1, 30parts by weight of glass fiber with a diameter of 10 μm and an averagelength of 3 mm (ECS03T275 GH made by Nippon Electric Glass Co., Ltd.)and 10 parts by weight of wollastonite (NYGLOS5: surface treated typewith a diaminosilane coupling agent, having an average fiber diameter of5 μm and an average fiber length of 65 μm made by Tomoe Engineering Co.,Ltd.), dry blend was carried out. This blend was melt mixed andpelletized using a co-rotating twin screw extruder TEM35 (L1/D1=47) madeby Toshiba Machine Co., Ltd., under conditions of cylindertemperature=320° C. and revolution speed=400 rpm to produce a polyamidecomposition. Results obtained are shown in Table 7.

EXAMPLE 18

Using 100 parts by weight of the polyamide obtained in Example 1, 30parts by weight of glass fiber with a diameter of 10 μm and an averagelength of 3 mm (ECS03T275 GH made by Nippon Electric Glass Co., Ltd.)and 10 parts by weight of mica (A-11 with an average particle size of 3μm supplied by TSUCHIYA KAOLIN IND. LTD.), dry blend was carried out.This blend was melt mixed and pelletized using a co-rotating twin screwextruder TEM35 (L1/D1=47) made by Toshiba Machine Co., Ltd., underconditions of cylinder temperature=320 to 350° C. and revolutionspeed=400 rpm to produce a polyamide composition. Results obtained areshown in Table 7.

COMPARATIVE EXAMPLE 12

A composition was prepared by compounding glass fiber into a polyamideaccording to the same method as in Example 14 except that the polyamideobtained in Comparative Example 1 was used, then injection molding ofthe composition was carried out. Results obtained are shown in Table 7.

TABLE 1 Comparative Comparative Example 1 Example 2 Example 3 Example 4Example 1 Example 2 Characteristics of Monomer Dicarboxylic AcidComponent ADA/CHDC ADA/CHDC ADA/CHDC ADA/CHDC ADA/CHDC ADA/CHDC (% bymole) (60/40) (60/40) (60/40) (60/40) (60/40) (60/40) Trans/Cis MolarRatio of CHDA 80/20 65/35 55/45 95/5 20/80 99.7/0.3 Diamine Component (%by mole) C6DA (100) C6DA (100) C6DA (100) C6DA (100) C6DA (100) C6DA(100) Characteristics of Polymer Melting Point: Tm² (° C.) 290 290 289291 288 293 Melting Enthalpy (J/g) 25 25 25 25 24 26 CrystallizationTemperature (° C.) 248 248 248 250 246 255 Glass Transition Temperature(° C.) 70 70 70 72 68 75 Number Average Molecular Weight 15,500 15,50015,000 15,000 15,000 14,500 (Mn) Molecular Weight Distribution 2.9 2.92.9 3.0 3.0 3.2 (Mw/Mn) Specific Gravity (Kg/m³) 1.12 1.12 1.12 1.121.12 1.12 Mechanical Properties of Polymer Tensile Strength (MPa) 85 8585 85 78 85 Tensile Elongation (%) 20 18 16 20 7 20 Flexural Modulus(Gpa) 2.9 2.9 2.9 2.9 2.8 2.9 Notched Izod Impact Strength 55 55 50 5547 55 (J/m) Heat Deflection Temperature 100 100 98 100 97 100 (° C.)Water Absorption Ratio 0.80 0.75 0.75 0.85 0.75 0.95 (% by weight)Retension of Strength after >95 >95 >95 >95 >95 >95 UV Irradiation (%)Depth of Crack after CaCl₂ 0.5 0.5 0.6 0.5 2.7 0.5 Treatment (μm)Appearance (Gloss at 60° C.) 75 75 75 70 77 50 ADA: Adipic Acid, CHDC:1,4-Cyclohexanedicarboxylic acid, C6DA: Hexamethylenediamine

TABLE 2 Compara- Comparative tive Example 5 Example 6 Example 3 Example4 Characteristics of Monomer Dicarboxylic Acid ADA/ ADA/ CHDC ADA/Component CHDC CHDC (100) CHDC (% by mole) (40/60) (85/15) (95/5)Trans/Cis Molar Ratio 80/20 80/20 80/20 80/20 of CHDA Diamine ComponentC6DA C6DA C6DA C6DA (% by mole) (100) (100) (100) (100) Characteristicsof Polymer Melting Point: 327 283 (Tm1 = 412) 270 Tm² (° C.) MeltingEnthalpy (J/g) 11 46 ND* 50 Crystallization 289 241 ND⁺ 225 Temperature(° C.) Glass Transition 90 55 ND⁺ 50 Temperature (° C.) Number Average15,000 14,500 13,000 16,500 Molecular Weight (Mn) Molecular Weight 3.03.0 3.0 3.0 Distribution (Mw/Mn) Specific Gravity 1.12 1.13 1.11 1.14(Kg/m³) Mechanical Properties of Polymer Tensile Strength 82 85 not 82(MPa) moldable Tensile Elongation (%) 11 25 25 Flexural Modulus 2.8 2.92.8 (Gpa) Notched Izod Impact 47 55 55 Strength (J/m) Heat Deflection120 87 not 79 Temperature (° C.) moldable Water Absorption 0.83 0.951.23 Ratio (% by weight) Retension of Strength >95 >95 >95 after UVIrradiation (%) Depth of Crack after no crack 1.8 >5 CaCl₂ Treatment(μm) Appearance 70 75 77 (Gloss at 60° C.) ADA: Adipic Acid, CHDC:1,4-Cyclohexanedicarboxylic acid, C6DA: Hexamethylenediamine ND*: Notdetected.

TABLE 3 Example 7 Example 8 Example 9 Example 10 Characteristics ofMonomer Dicarboxylic Acid CHDC CHDC CHDC CHDC/ADA Component (100) (100)(100) (20/80) (% by mole) Trans/Cis Molar Ratio 80/20 80/20 80/20 80/20of CHDA Diamine Component C8DA C9DA C12DA C11DA (% by mole) (100) (100)(100) (100) Characteristics of Polymer Melting Point: 325 313 285 262Tm² (° C.) Melting Enthalpy (J/g) 11 18 25 22 Crystallization 276 271232 215 Temperature (° C.) Glass Transition 86 76 57 52 Temperature (°C.) Number Average 15,500 15,500 15,000 15,000 Molecular Weight (Mn)Molecular Weight 3.5 3.5 3.6 3.4 Distribution (Mw/Mn) Specific Gravity1.09 1.09 1.09 1.11 (Kg/m³) Mechanical Properties of Polymer TensileStrength 85 85 85 85 (MPa) Tensile Elongation (%) 12 18 25 22 FlexuralModulus 2.8 2.8 2.8 2.8 (Gpa) Notched Izod Impact 45 55 55 55 Strength(J/m) Heat Deflection 113 98 81 75 Temperature (° C.) Water Absorption0.53 0.52 0.50 0.65 Ratio (% by weight) Retension ofStrength >95 >95 >95 >95 after UV Irradiation (%) Depth of Crack afterno crack no crack no crack no crack CaCl₂ Treatment (μm) Appearance 7077 77 77 (Gloss at 60° C.) CHDC: 1,4-Cyclohexanedicarboxylic acid, C8DA:Octamethylenediamine, C9DA: Nonanemethylenediamine, C12DA:Dodecamethylenediamine, C11DA: Undecamethylenediamine

TABLE 4 Comparative Comparative Comparative Example 5 Example 6 Example7 Characteristics of Monomer Dicarboxylic Acid Component CHDC CHDCADA/CHDC (% by mole) (100) (100) (15/85) Trans/Cis Molar Ratio of 20/8050/50 20/80 CHDA Diamine Component C8DA (100) C11DA C11DA (% by mole)(100) (100) Characteristics of Polymer Melting Point: Tm² (° C.) 323 282267 Melting Enthalpy (J/g) 10 22 25 Crystallization Temperature 275 239225 (° C.) Glass Transition Temperature 85 75 55 (° C.) Number AverageMolecular 15,000 14,500 14,500 Weight (Mn) Molecular Weight 3.5 3.7 3.5Distribution (Mw/Mn) Specific Gravity (Kg/m³) 1.09 1.09 1.09 MechanicalProperties of Polymer Tensile Strength (MPa) 75 85 85 Tensile Elongation(%) 5 8 11 Flexural Modulus (Gpa) 2.8 2.8 2.8 Notched Izod ImpactStrength 35 40 50 (J/m) Heat Deflection Temperature 110 100 78 (° C.)Water Absorption Ratio 0.55 0.5 0.5 (% by weight) Retension of Strengthafter >95 >95 >95 UV Irradiation (%) Depth of Crack after CaCl₂ no crackno crack no crack Treatment (μm) Appearance (Gloss at 60° C.) 70 45 60CHDC: 1,4-Cyclohexanedicarboxylic acid, C11DA: Undecamethylenediamine

TABLE 5 Example Example Example Example 11 12 13 14 Characteristics ofMonomer Dicarboxylic Acid ADA/ ADA/ ADA/ ADA/ Component (% by mole)CHDC/ CHDC/ CHDC/ CHDC/ IPA IPA IPA IPA (84/8/8) (84/8/8) (73/13/14)(40/30/30) Trans/Cis Molar Ratio of 80/20 60/40 80/20 80/20 CHDA DiamineComponent C6DA C6DA C6DA C6DA (% by mole) (100) (100) (100) (100)Characteristics of Polymer Melting Point: 257 257 250 242 Tm² (° C.)Melting Enthalpy (J/g) 36 36 28 22 Crystallization 217 217 212 199Temperature (° C.) Glass Transition 55 55 53 83 Temperature (° C.)Number Average 15,500 15,500 15,000 13,500 Molecular Weight (Mn)Molecular Weight 2.7 2.7 2.9 3.2 Distribution (Mw/Mn) Specific Gravity(Kg/m³) 1.13 1.13 1.12 1.11 Mechanical Properties of Polymer TensileStrength (MPa) 85 85 86 85 Tensile Elongation (%) 22 20 20 15 FlexuralModulus (Gpa) 2.9 2.9 2.8 2.9 Notched Izod Impact 58 58 60 50 Strength(J/m) Heat Deflection 75 75 75 98 Temperature (° C.) Water AbsorptionRatio 0.98 0.95 0.88 0.58 (% by weight) Retension ofStrength >95 >95 >95 >95 after UV Irradiation (%) Depth of Crack after0.5 1.0 0.1 no crack CaCl₂ Treatment (μm) Appearance 80 80 80 75 (Glossat 60° C.) ADA: Adipic Acid, CHDC: 1,4-Cyclohexanedicarboxylic acid,C6DA: Hexamethylenediamine, IPA: Isophthalic Acid

TABLE 6 Compara- Compara- Compara- Compara- tive tive tive tive ExampleExample Example 8 Example 9 10 11 Characteristics of MonomerDicarboxylic Acid ADA/ ADA/ ADA/ ADA/ Component (% by mole) CHDC/ CHDC/TPA/ IPA IPA IPA IPA (82/18) (84/8/8) (84/8/8) (84/8/8) Trans/Cis MolarRatio of 99.7/0.3 45/55 — — CHDA Diamine Component C6DA C6DA C6DA C6DA(% by mole) (100) (100) (100) (100) Characteristics of Polymer MeltingPoint: 260 255 249 240 Tm² (° C.) Melting Enthalpy (J/g) 38 36 44 34Crystallization 220 215 211 192 Temperature (° C.) Glass Transition 6053 50 60 Temperature (° C.) Number Average 15,500 15,500 15,000 15,000Molecular Weight (Mn) Molecular Weight 2.7 2.7 3.1 2.9 Distribution(Mw/Mn) Specific Gravity 1.13 1.13 1.14 1.14 (Kg/m³) MechanicalProperties of Polymer Tensile Strength (MPa) 85 75 83 86 TensileElongation (%) 22 7 25 10 Flexural Modulus (Gpa) 2.9 2.9 2.9 2.9 NotchedIzod Impact 58 45 60 5.1 Strength (J/m) Heat Deflection 78 75 75 75Temperature (° C.) Water Absorption Ratio 1.12 1.00 0.88 1.03 (% byweight) Retension of Strength >95 >95 80 90 after UV Irradiation (%)Depth of Crack after 0.5 2.0 0.1 2.2 CaCl₂ Treatment (μm) Appearance 6580 70 80 (Gloss at 60° C.) ADA: Adipic Acid, CHDC:1,4-Cyclohexanedicarboxylic acid, C6DA: Hexamethylenediamine, IPA:Isophthalic Acid, TPA: Terephthalic Acid

TABLE 7 Comparative Example 15 Example 16 Example 17 Example 18 Example12 Characteristics of Monomer Dicarboxylic Acid Component ADA/CHDCADA/CHDC/IPA ADA/CHDC ADA/CHDC ADA/CHDC (% by mole) (60/40) (84/8/8)(60/40) (60/40) (60/40) Trans/Cis Molar Ratio of CHDA 80/20 80/20 80/2080/20 20/80 Diamine Component (% by mole) C6DA (100) C6DA (100) C6DA(100) C6DA (100) C6DA (100) Characteristics of Polymer Melting Point:Tm² (° C.) 290 257 290 290 288 Melting Enthalpy (J/g) 25 36 25 25 24Crystallization Temperature (° C.) 248 217 248 248 246 Glass TransitionTemperature (° C.) 70 55 70 70 68 Number Average Molecular Weight (Mn)15,500 15,500 15,500 15,500 15,000 Molecular Weight Distribution (Mw/Mn)2.9 2.7 2.9 2.9 3.0 Specific Gravity (Kg/m³) 1.12 1.13 1.12 1.12 1.12Inorganic filler and its compounding GF* GF* GF*/Wollastonite GF*/MicaGF* ratio (parts by wt. based on 100 40 40 30/10 30/10 40 parts by wt.of polyamide) Mechanical Properties of Polymer Tensile Strength (MPa)210 200 190 190 175 Tensile Elongation (%) 7.5 7.5 5.5 5.5 4 FlexuralModulus (Gpa) 12 12 11 11 12 Notched Izod Impact Strength (J/m) 110 11090 90 100 Heat Deflection Temperature (° C.) 275 240 275 275 275 WaterAbsorption Ratio (% by weight) 0.25 0.35 0.15 0.13 0.25 Retension ofStrength after UV >95 >95 >95 >95 >95 Irradiation (%) Depth of Crackafter CaCl₂ no crack no crack no crack no crack 0.1 Treatment (μm)Appearance (Gloss at 60° C.) 63 70 60 60 63 ADA: Adipic Acid, CHDC:1,4-Cyclohexanedicarboxylic acid, C6DA: Hexamethylenediamine, GF*: glassfiber

INDUSTRIAL APPLICABILITY

The polyamide of the present invention is a polymer having well balancedphysical properties and superior characteristics such as toughness,impact properties, heat resistance, light resistance, light weight, lowwater absorption, chemical resistance and appearance as well as anextremely superior moldability, and can be suitably used as a moldingmaterial for automotive parts, electric/electronics parts, industrialmaterials, engineering materials, daily household goods and the like.

1. A polyamide obtained by thermal polycondensation of (a) dicarboxylicacid components comprising 10 to 80% by mole based on the total moles ofcarboxylic acid components of 1,4-cyclohexanedicarboxylic acid having atrans/cis molar ratio of 55/45 to 97/3 and (b) an aliphatic diaminecomponent.
 2. The polyamide in accordance with claim 1, wherein saidtrans/cis molar ratio of 1,4-cyclohexanedicarboxylic acid is 55/45 to90/10.
 3. The polyamide in accordance with claim 1, wherein saidtrans/cis molar ratio of 1,4-cyclohexanedicarboxylic acid is 70/30 to30/10.
 4. The polyamide in accordance with claim 2, wherein thedicarboxylic acid component other than 1,4-cyclohexanedicarboxylic acidis an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and/or anaromatic dicarboxylic acid and the aliphatic diamine component is analiphatic diamine unit having 4 to 12 carbon atoms.
 5. The polyamide inaccordance with claim 3, wherein the dicarboxylic acid component otherthan 1,4-cyclohexanedicarboxylic acid is an aliphatic dicarboxylic acidhaving 6 to 12 carbon atoms and/or an aromatic dicarboxylic acid and thealiphatic diamine component is an aliphatic diamine unit having 4 to 12carbon atoms.
 6. The polyamide in accordance with claim 3, wherein thedicarboxylic acid component other than 1,4-cyclohexanedicarboxylic acidis adipic acid and/or isophthalic acid and the aliphatic diaminecomponent is hexamethylenediamine.
 7. The polyamide in accordance withclaim 6, wherein the dicarboxylic acid component other than1,4-cyclohexanedicarboxylic acid is adipic acid and/or isophthalic acidand the aliphatic diamine component is hexamethylenediamine.
 8. Thepolyamide in accordance with claim 6, wherein the dicarboxylic acidcomponents are composed of 10 to 60% by mole of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of 70/30to 90/10, 20 to 90% by mole of adipic acid and 0 to 40% by mole ofisophthalic acid, based on the total moles of1,4-cyclohexanedicarboxylic acid, adipic acid and isophthalic acid asbeing 100%.
 9. The polyamide in accordance with claim 7, wherein thedicarboxylic acid components are composed of 10 to 60% by mole of1,4-cyclohexanedicarboxylic acid having a trans/cis molar ratio of 70/30to 90/10, 20 to 90% by mole of adipic acid and 0 to 40% by mole ofisophthalic acid, based on the total moles of1,4-cyclohexanedicarboxylic acid, adipic acid and isophthalic acid asbeing 100%.
 10. The polyamide in accordance with claim 1, wherein saidpolyamide has a number average molecular weight (Mn) of 7,000 to 100,000and a melting point of 210 to 340° C.
 11. The polyamide in accordancewith claim 3, wherein said polyamide has a number average molecularweight (Mn) of 7,000 to 100,000 and a melting point of 210 to 340° C.12. The polyamide in accordance with claim 6, wherein said polyamide hasa number average molecular weight (Mn) of 7,000 to 100,000 and a meltingpoint of 210 to 340° C.
 13. The polyamide in accordance with claim 7,wherein said polyamide has a number average molecular weight (Mn) of7,000 to 100,000 and a melting point of 210 to 340° C.
 14. The polyamidein accordance with claim 9, wherein said polyamide has a number averagemolecular weight (Mn) of 7,000 to 100,000 and a melting point of 210 to340° C.
 15. A molded article comprising the polyamide in accordance withclaim
 1. 16. A molded article comprising the polyamide in accordancewith claim
 7. 17. A molded article comprising the polyamide inaccordance with claim
 9. 18. A molded article comprising the polyamidein accordance with claim 14.